The present invented process relates to a process for the cleavage of high molecular weight polyethylene glycol monoalkyl ethers to prepare lower molecular weight products. In particular the present process relates to a unique catalytic process for the hydrolysis of high molecular weight polyethylene glycol monoalkyl ethers.
(Poly)ethylene glycol ethers are known compounds having uses in numerous applications wherein their excellent solvent characteristics may be applied. Examples include paint and other coating formulations, chemical processing and extraction systems, printing inks, textiles, adhesives and sealants, etc. In general, lower molecular weight glycol ethers, particularly monoalkyl ethers of ethylene glycol or diethylene glycol, are most useful in such applications due to their lower viscosities and boiling points compared to the higher molecular weight compounds.
(Poly)ethylene glycol ethers may suitably be prepared by several known techniques. One such process involves the acid catalyzed reaction between an alkanol, especially a lower alkanol, and ethylene oxide. According to this and other known processes, relatively high yields of the desired lower alkyl monoether of ethylene glycol are prepared. Disadvantageously however, it is extremely difficult to selectively limit such processes to prepare only ethylene glycol monoethers without concomitant formation of diethylene-, triethylene- and higher polyethylene glycol monoethers. Therefore, to a lesser or greater degree, the commercial production of ethylene glycol monoethers also results in production of "highers".
While it is a relatively simple task to separate such reaction products, the manufacturer is often faced with an imbalance between production and demand. Usually, more triethylene glycol monoethers and higher polyethylene glycol monoethers are prepared by the above acid catalyzed process than can readily be absorbed in commercial applications.
In order to overcome this difficulty, improved catalysts and novel methods of selectively preparing mono- and diethylene glycol monoethers are often sought. Such processes frequently require expensive catalysts or processing conditions or may involve different reactants and equipment than traditionally employed. In addition, while a new process may give a temporary shift in the relative amounts of products formed, they generally fail to provide any flexibility in the event that lesser or greater amounts of one product or another are later required.
In addition, certain cyclic ether compounds, specifically dioxane, could easily be prepared by a manufacturer of glycol ether highers if a method of hydrolytic cleavage and ring closure were available.
It would be desirable to provide a method to correct an imbalance in production of polyethylene glycol monoether highers. Additionally, it would be desirable to provide such a process that does not require the manufacturer to extensively modify existing processes for preparing ethylene glycol monoethers. It would further be desirable to provide a process that allows flexibility in the preparation of (poly)ethylene glycol monoethers whereby the manufacturer may easily alter the amounts of higher oligomers prepared in response to changing market requirements. Finally, it would be desirable to provide a process that allows the operator to prepare a variety of hydrolytic decomposition products of polyethylene glycol monoethers including glycols, lower glycol monoethers and cyclic ethers such as dioxane.